Since the mobile phones are introduced to the market, they are popular around the world and become necessary to one's life. Besides, more and more electronic devices, such as PDAs, laptops, tablet PCs, or consumer electronics integrate wireless communication capabilities. For mobile electronic devices mentioned above, an antenna is the core component for wireless connections. Therefore, it is always desirable to scale down the size, improve the performance, and increase the pattern receiving diversity of the antenna.
U.S. Pat. No. 6,166,694 discloses a miniature, built-in dual band antenna which is suitable for use in mobile devices, wherein the built-in antenna includes two spiral conductor arms which are of different lengths and capable of being tuned to different frequency bands. And U.S. Pat. No. 6,407,715 discloses an antenna having a conductive ground plate, a conductive first plate set above the ground plate, and a signal feed electrically connected to the ground plate and the first plate. The first plate has two slots extending from two edges of the first plate for receiving or sending signals.
U.S. Pat. No. 6,414,642 discloses a slot antenna having a pair of orthogonally oriented front and rear reflector panels. The orthogonal slot antenna assembly disclosed is useful in laptop computers or other wireless devices benefiting from a compact and yet robust antenna which radiates with multiple patterns in various multiple orientations. Also U.S. Pat. No. 6,339,400 discloses an antenna implementation in which two whip-like/slot embedded antennas are placed on the left and right edge of the display. Using two antennas instead of one antenna will reduce the blockage caused by the display in some directions and provide space diversity to the communication system.
As antennas embedded in mobile devices become increasingly popular, a need exists for a compact antenna having low manufacture costs and being able to receive signals from all directions.